As is known, among the various operating phases that are carried out in a malthouse, one of them is that of steeping or pregermination of the barley. During this operating phase, it becomes necessary to stir the product with the purpose of preventing it from caking and consequently achieving uniform humidification at the same time it is necessary to eliminate the CO.sub.2 which is produced during the pregermination which must occur in a controlled way so that the grain does not spoil, for which purpose it is also necessary to carry out an appropriate cooling.
This is generally achieved by installing in the base of the steeping vat a plurality of adequately distributed injectors through which compressed air is blown in such a way that the air, on rising between the mass of grain, engenders the stirring of the same, carries out oxygenation of the water, removes the CO.sub.2 and also removes the heat produced by the germination.
More specifically, the said injectors are positioned inside a false bottom defined by an upper, perforated sheet through which the air exits. However, this solution which is acceptable in conical-bottomed vats, presents significant problems when the steeping vat is flat-bottomed and above all when the said vat has very considerable dimensions, as occurs in large malthouses.
More specifically, in such cases and so that the air-blowing is effective, it is necessary to arrange the injectors very close to one another, which implies very significant costs, as much for replacement as for maintenance, since the injectors become considerably soiled and require periodic and very frequent exchanges.